Purchase Order – HRSD Virginia Initiative Plant

EnviroMix announced today that it has been awarded a significant contract to supply its mixing and controls technology as part of a project to upgrade the Hampton Roads Sanitation District (HRSD) Virginia Initiative Plant (VIP) in Norfolk, Virginia. This 40 million gallon per day (MGD) design flow wastewater treatment facility will provide additional nitrogen removal capabilities while maintaining biological phosphorous removal to achieve annual average effluent concentrations of 5 mg/l of total nitrogen (TN) and 1 mg/l of total phosphorous (TP).

In order to improve the nutrient removal process at this plant, the owner is implementing the BioMix™ Compressed Gas Mixing System to mix the versatile bioreactors (VBRs/Swing Zones) and the mixing limited zones, which are at the tail-end of four aeration basins. The BioMix system will use less than 50% of the energy that would have been required using conventional submersible mixers.

By decoupling aeration from mixing, the diffused aeration system in the aeration basins can be turned down or even off to prevent high concentrations of dissolved oxygen disrupting subsequent anoxic zones. Moreover during normal operation, the BioMix system will operate independently of the diffused aeration system to mix the VBRs in anoxic mode for denitrification.

Due to the complicated geometry and the multiple zones, 24 submersible mixers would have been required, but the BioMix technology is able to mix the VBRs and a portion of the aeration basins with one air compressor, greatly reducing maintenance as well.

Dr. Charles Bott, chief of research and development for the HRSD, stated, “As part of our strategic plan, HRSD strives to implement innovative technologies to improve energy efficiency while maintaining the required level of treatment. The high efficiency and operational flexibility offered by the BioMix Compressed Gas Mixing System aligns well with these objectives.”

The BioMix system is expected to be operational by July 2016. EnviroMix is pleased to provide HRSD’s VIP facility with an innovative, highly flexible and energy-efficient mixing system as part of their nutrient removal project.